This invention relates generally to a self-propelled underwater trenching apparatus. More particularly the present invention is concerned with the self-propelled underwater buoyant apparatus for burying pipelines or cables and the like in a trench formed in the bottom of a body of water. Uniquely, the present invention further relates to an underwater apparatus for burying pipelines or cables by cutting a trench in the bottom formation and overcome any obstruction on the pipeline to the continuous movement of the apparatus along the pipeline formation and disposing of the cuttings so produced.